1. Technical Field
Example embodiments relate generally to voltage controlled oscillators (VCOs), such as VCOs being applicable to various integrated circuits and phase locked loops (PLLs) including the VCOs.
2. Description of the Related Art
A VCO controls a frequency of an output signal based on a voltage of an input signal. VCOs can be roughly divided into two categories depending upon a structure. These categories include a ring VCO, which includes a plurality of inverters, and a LC VCO, which includes an inductor and a capacitor. The VCO may be included in various integrated circuits, such as a PLL. Recently, various technologies have been researched for operating the VCO based on a relatively low power supply voltage.